This invention relates to the quench cooling and cleaning of raw synthesis or fuel gas containing entrained particulate carbon as produced by the partial oxidation of a liquid hydrocarbonaceous fuel. More specifically, it relates to an apparatus for continuously separating into its component materials a stream of liquid organic extractant-carbon-water dispersion from a decanter that is employed in the synthesis or fuel gas quench cooling and cleaning operation.
Raw effluent gas leaving a partial oxidation gas generator may comprise principally CO, H.sub.2, CO.sub.2 and H.sub.2 O together with other gaseous constituents and minor amounts of entrained finely divided carbon. The particulate carbon is commonly referred to as soot. Cleaning and purifying the raw effluent gas to produce synthesis gas or fuel gas usually starts with the removal of the particulate carbon and any other entrained solids. This will extend the life of any catalyst or solvent that may be later contacted by the process gas stream. Synthesis gas is important commercially as a source of feed gas for the synthesis of hydrocarbons or oxygen containing organic compounds, or for producing hydrogen or ammonia.
Entrained particulate carbon may be removed from the raw effluent gas by quenching and scrubbing with water such as described in coassigned U.S. Pat. No. 3,232,728. Cleaning the effluent gas by scrubbing with an oil-carbon slurry is described in coassigned U.S. Pat. No. 3,636,261. Recovery of the particulate carbon from carbon-water dispersions by the steps of adding a light oil to the carbon-water dispersion, separating water and light oil-carbon dispersion in a decanter, mixing the light oil-carbon dispersion with heavy oil and heating in a preheater, and vaporizing the light oil in a flash drum or distillation tower is described in coassigned U.S. Pat. Nos. 2,999,741; 2,992,906, 3,004,179; and 4,134,740. Typical decanting procedures are described in coassigned U.S. Pat. Nos. 3,980,592 and 4,014,786. However, the subject process is more thermally efficient and eliminates costly distillation equipment. Further, more concentrated liquid extractant-carbon dispersions from the decanter may be handled; and, dispersions of liquid hydrocarbonaceous fuel and carbon are easily obtained which may be recycled to the gas generator as a portion of the fuel.